Field
This disclosure relates to a compound and an organic light-emitting device including the same.
Description of the Related Technology
Organic light emitting devices are self-emission devices that have wide viewing angles, high contrast ratios, short response time, and excellent brightness, driving voltage, and response speed characteristics, and produce full-color images.
A typical organic light-emitting device has a structure including a substrate, and an anode, a hole transport layer, an emission layer, an electron transport layer, and a cathode which are sequentially stacked on the substrate. The hole transport layer, the emission layer, and the electron transport layer are organic thin films formed of organic compounds.
An organic light-emitting device having operates by generating light.
When a voltage is applied between the anode and the cathode, holes injected from the anode pass the hole transport layer and migrate toward the emission layer, and electrons injected from the cathode pass the electron transport layer and migrate toward the emission layer. Carriers, such as holes and electrons, are recombined in the emission layer to produce excitons. Then, the excitons are transitioned from an excited state to a ground state, thereby generating light.
A material that has excellent electric stability, high charge transport capability or luminescent capability, high glass transition temperature, and high crystallization prevention capability is desirable.
In determining luminescent efficiency, a critical factor for organic light-emitting devices is a luminescent material. As a luminescent material, fluorescent materials are being widely used. However, according to the mechanism of electric luminescence, in theory, development of phosphorescent materials may lead to a 4-fold increase in luminescent efficiency. Iridium (III) complex-based phosphorescent materials such as (acac)Ir(btp)2, Ir(PPY)3, and Firpic may be used for red, green, and blue emission, respectively.

4,4′-N,N′-dicarbazole-biphenyl (CBP) is one example of a phosphorescent host material is widely.
Although advantageous in terms of light-emitting characteristics existing light-emitting materials may have low glass transition temperature and thus may be deteriorated during high-temperature deposition under vacuum. For an OLED, power efficiency=(π/voltage)×current efficiency. Since power efficiency is in reverse proportion to voltage, higher power efficiency is needed to obtain a lower consumption power of an OLED. An OLED using a phosphorescent luminescent material has higher current efficiency (cd/A) than an OLED using a fluorescent luminescent material, but when BAlq or CBP is used as a phosphorescent luminescent material host, compared to an OLED using a fluorescent material, a formed OLED may have high driving voltage, thereby showing a relatively low power efficiency (lm/w).

Also, the an OLED using such material may have unsatisfactory lifetime characteristics. Accordingly, there is a demand for the development of a host material with excellent performance.